Introduction: It is thought that sex hormone binding protein (SHBG) is involved in glucose homeostasis in addition to regulate the levels of sex hormones. Clinical studies associate reduced SHBG concentrations with insulin resistance (IR).
Objective: To evaluate the relationship of SHBG with IR and hyperandrogenism markers in a group of adolescents affected with polycystic ovarian syndrome (PCOS), and how weight could affect these markers.
Patients and methods: 35 women aged 1219 years, who fulfilled Rotterdam diagnostic criteria for PCOS were evaluated. Glucose, insulin, SHBG, testosterone, LH and FSH were determined among other biochemical variables. Homeostasis model assessment-estimated IR (HOMA-IR) and free androgen index (FAI) were calculated. Patients were divided into: normal weight (BMI<25 kg/m2 (n=17) and overweight/obesity (BMI>25 kg/m2 (n=19)).
Results: SHBG was significantly lower (22.1±11.8 nmol/l vs 35±16.9 nmol/l, P=0.015) and HOMA-IR and insulin were significantly higher (5.4±2.8 vs 2.3±0.63 P=0.001; 25.6±13.7 mUI/ml vs 12.8±5.3 mUI/ml P=0.003) in girls with overweight/obesity respected to the normal weight group. In overweight girls SHBG levels inversely correlated with BMI (r=−0.521, P=0.001), insulin (r=−0.476, P=0.011), HOMA-IR (r=−0.438, P=0.025) and FAI (r=−0.651, P<0.001), whereas in the normal-weight group SHBG inversely correlated with FAI (r=−0.736, P=<0.001), testosterone (r=−0.476, P=0.039) and hirsutism (r=−0.491, P=0.033) and positively with FSH (r=0.589, P=0.021). Stepwise regression analysis showed HOMA-IR as the only independent variable explaining 43% of SHBG variability (P=0.011) in overweight/obesity girls, whereas in the normal weight group, FSH was the only independent predictor explaining 34.7% of changes in SHBG (P=0.021).
Conclusions: In girls affected with PCOS, serum SHBG is subjected to different regulation according to the weight. In overweight/obese group, HOMA-IR is an independent factor which explains SHBG variability, so this supports the hypothesis that could be an early marker of IR in this group. However, in the normal weight group SHBG variability is explained by FSH.
01 Oct 2015 - 03 Oct 2015